225 research outputs found

    Domination changing and unchanging signed graphs upon the vertex removal

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    A subset S of V (Σ) is a dominating set of Σ if |N⁺(v) ∩ S| > |N⁻(v) ∩ S| for all v ∈ V − S. This article is to start a study of those signed graphs that are stable and critical in the following way: If the removal of an arbitrary vertex does not change the domination number, the signed graph will be stable. The signed graph, on the other hand, is unstable if an arbitrary vertex is removed and the domination number changes. Specifically, we analyze the change in the domination of the vertex deletion and stable signed graphs.Publisher's Versio

    Biology of the economically important Indian seaweeds-a review

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    Studies on the biological aspects of economically important Indian seaweeds are reviewed in this paper. These include the taxonomy and ecological studies at different localities along the Indian coast. The growth pattern, periods of maximum growth, fruiting seasons for plants such as Cystoseira indica, Sargassum, Turbinaria, Gracilaria verrucosa and Gelidiella acerosa have been studied. Commercial harvesting is suggested during peak growth periods to obtain larger quantity of raw materials and better yield of finished products. Spore shedding and the period of maximum sporulation which vary from one seaweed to another has been studied by estimation of spore output and observations on the liberation of spores. Information is available on the germination of spores, survival rate of germlings, culture of germlings and life history studies

    Seaweed and seagrass resources

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    All macroscopic algae occurring in the marine habitat and coastal bracl<ish waters a'e known as seaweeds. They from one of the important marine living resources and belong to four major classes namely Chlorophyceae (green algae), Phaeophyceae (brown algae), Rhodoyhyceae (red algae) and Cyanophyceae (blue-green algae). Seaweeds are the only source for the production of phytochemicals namely agar-agar, carrageenan and algin, which are extensively used in various industries such as food, confectionary, textiles, pharmaceuticals, dairy and paper industry mostly as gelling, stabilising and thickening agents. Seaweeds are also used as human food animal feed and manure in several countries

    Ponovni opis, biologija, životni ciklus, ponašanje i ekotip Sphedanolestes minusculus Bergroth (Hemiptera: Reduviidae)

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    Sphedanolestes minusculus Bergroth lays pale yellow eggs in batches. Eggs are glued to each other and to the substratum with cementing material. The average number of eggs per female was 63.33 ± 21.77. The eggs hatch in 7.80 ± 0.41 days. The average developmental period from I instar to V instar was 48.43 ± 7.39days. The longevity of the male (80.16 ± 5.23) was shorter (96.77 ± 11.88) than that of the female. The preoviposition period was 12.55 ± 3.43 days and the male and female sex ratio was 1: 1.5. The innate capacity of natural increase (rc) was 0.061 with a gross reproduction rate (mx) of 91.671 females per female. Mean length of generation (Tc) was 76.310 days. Redescriptions of adult and descriptions of egg and nymphal instars are given with illustrations. Predatory and mating behaviour exhibited sequential events as in other reduviids. Prey-deprived predators took less time to approach, capture and pin the prey. Individuals of S. minusculus collected from three different ecological and geomorphological habitats viz., Olavakod tropical rainforest, Sunkankadai scrub jungle and Aralvaimozhi semiarid zone exhibited pronounced diversities in their oviposition pattern, hatchability, incubation and stadial periods, nymphal mortality, adult longevity and sex ratio. These diversities are considered a specially adapted biological function collectively called ecotypism.Sphedanolestes minusculus Bergroth polaže blijedo žuta jaja u gomilicama. Jaja su ljepljivom tvari slijepljena međusobno kao i za podlogu. Srednja vrijednost broja jaja po ženki je bila 63,33 ± 21,77. Ličinke su se izvalile u 7,80 ± 0,41 dana. Srednja vrijednost razvojnog perioda od I do V stadija bila je 48,43 ± 7.39 dana. Dužina života mužjaka (80,16 ± 5,23) bila je kraća (96,77 ± 11,88) nego ženki. Preovipozicija jaja je trajala 12,55 ± 3.43 dana a omjer između mužjaka i ženki je bio 1:1,5. Urođen, svojstven kapacitet prirodnog porasta (rc) je bio 0,061 s maksimalnim omjerom reprodukcije (mx) od 91,671 ženki. Prosječna dužina života jedne generacije (Tc) bila je 76, 310 dana. Ponovo su opisani odrasli, a na novo jaja i ličinački stadiji prikazani slikama. Složeno predatorsko ponašanje i ponašanje tijekom parenja slijedilo je pravilan tok kao kod drugih vrsta porodice Reduviidae. Ovi predatori su brzi u lovu i pridržavanju ulova. Jedinke Sphedanolestes minusculus su bile sakupljane u tri različita ekološka i geomorfološka staništa: Olavakod - tropska kišna šuma, Sunkankadai - guštara đungle i Aralvaimozhi - semiaridna zona. Opisane su različitosti u: njihovim ovipozicijskim uzorcima, izlijeganju jaja, vremenu inkubacije, trajanju razvojnih stadija, ličinačkoj smrtnosti, dužini života odraslih, te omjeru spolova. Te razlike u opisanim karakteristikama smatraju se posebno prilagođenim biološkim funkcijama koje zajednički nazivamo ekotip

    BIOLOGIJA, PONAŠANJE I ODNOS ŽRTVA - PREDATOR U VRSTE Sphedanolestes Variabilis Distant (INSECTA: HEMIPTERA: REDUVIIDAE: HARPACTORINAE), POTENCIJALNOGA PREDATORA ŠTETNIKA IZ REDA LEPIDOPTERA

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    Sphedanolestes variabilis Distant laid light brown colour eggs singly as well as in small clusters of 5 to 10 eggs. The incubation period was 6.92±0.29 days. The stadial durations of I,II,III,IV and V instar nymphs were 6.83±0.58, 6.83±0.94, 6.58±1.56, 8.42±2.68 and 8.67±2.23 and 19.67±3.44 days respectively. Adult males and females lived for 93.83±13.04 and 102.83±12.69 days and their sex ratio was 1: 1 (male and female). The sequential acts of predation as well as that of mating conform to these of other harpactorine reduviids. S. variabilis exhibited Holling\u27s type II functional response as indicated by the positive correlation obtained between the prey density and the number of prey killed by the predator. The attack ratio decreased as the prey density was increased. A negative correlation was obtained between the searching time and the prey density.Sphedanolestes variabilis Distant odlaže jaja svijetlosmeđe boje pojedinačno ili u skupinama od 5 do 10 jaja. Inkubacijsko razdoblje traje 6,92 ± 0,29 dana. Razvojni stadiji I., II., III., IV. i V. faze nimfe jesu 6,83 ± 0,58, 6,83 ± 0,94, 6,58 ± 1,56, 8,42 ± 2,68 i 8,67 ± 2,23 i 19,67 ± 3,44 dana. Odrasli mužjaci i ženke živjeli su 93,83 ± 13,04 i 102,83 ± 12,69 dana, a omjer spolova bio je 1:1 (muški i ženski). Prema predatorstvu i parenju ta je vrsta u skladu s drugim vrstama iz porodice Readuviidae. Da bi se opisao odnos žrtva-plijen, korišten je model Holling tip II., koji je pokazao pozitivnu korelaciju između gustoće plijena i broja plijena ubijenih od predatora. Omjer napada smanjen je kako je gustoća plijena bila povećana. Negativna korelacija dobivena je između vremena pronalaska plijena i gustoće plijena

    Bioactivity in marine algae

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    Marine algae have been reponed to possess a wide range of bio active properties (Hashimoto 1979, Baslow 1969, Hoppe, et al. 1979, Hoppe et al. 1984, Blunden et al. 1981, Cocamese et al. 1981, Ramamurthy et al. 1967, Mc Lachan 1964, Byrkholder and Sharma 1969. Conover and Sieburth 1964, Garber et al. 1958). Quite recently, Naqvi et al. (1980) studied the bioactivities of 25 species of marine algae and sea grasses collected mainly from the North Eastern coast of India and a few from the coast of Tamil Nadu

    Facile synthesis of silver nanoparticles, anti-inflammatory, antibacterial and photocatalytic activities using Pogostemon speciosus Benth. An endemic medicinal plant

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    The development of biologically enthused green synthesis of silver nanoparticles (SNPs) has concerned significant global awareness about medical science and disease treatment. This paper discusses the green synthesis of SNPs using organic green sources; here we report a facile bottom-up ‘green’ route for the synthesis of SNPs using aqueous leaves extract of Pogostemon speciosus (Benth.) and evaluate its in-vitro anti-inflammatory, antibacterial and photocatalytic activities. The nanoparticles were investigated for the preparation of denaturation particles with PSLASNPs and the evaluation of anti-inflammatory activity with Protein denaturation and HRBC stabilization assays. Later, these PSLASNPs were studied for their potential role in antibacterial activity by well diffusion method, and Photocatalytic activity on degradation of dyes was demonstrated by using dyes Crystal violet, Coomassie blue, and Congo red. At 1000 µg/ml, the PSLASNPs have the greatest prevention of protein denaturation (71.92±1.37%), whilst the stabilization of the HRBC membrane exhibited significant anti-inflammatory action (64.39±1.61 %). The PSLASNPs showed the best antibacterial activity at the concentration of 10 µg/ml against Bacillus subtilis (8.2 mm), followed by Pseudomonas stuberia (6.2 mm) and Escherichia coli (6.4 mm), Staphylococcus aureus (5.3 mm), Staphylococcus gallinarium (4.5 mm) respectively at the same concentrations. Crystal violet, Coomassie blue, and Congo red were used for Photocatalytic activity on the breakdown of dyes. After 35 minutes, the degradation process was determined to be complete by the transformation of the reaction mixture's color to colorless. As a result, the PSLASNPs have anti-inflammatory, antibacterial, and photocatalytic activities

    Occurrence and growth of the commercially important red algae in fish culture pond at Mandapam

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    The red algae Gracilaria edulis, Hypnea valenliae, Acanthophora spicifera ard Sarconema irdica have been observed to occur arrl grow in a culture pard. Ove- a period of eight month s, the algae grew to lJ4 kg in the pard of 800 sq m. The hyd rological cordilions in the porn are compared to those in the sea containing natursl beds of these algae during the periro of observations. This occurrence ard growth may open up the ,,4. possibility of growing these algae in culture pards providing the requisite hyd rological ard nutrient corditions

    Seaweed resources of the Tuticorin-Tiruchendur coast, Tamil Nadu, India

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    The southern coast of Tamil Nadu (Mandapam to Kanyakumari) supports luxuriant growth of economic seaweeds. The entire indigenous phycocoUoid industry of the country gets the raw material from this region and during the last two decades, due to indiscriminate harvesting, there has been over-exploitation of the resource. The present paper deals with survey conducted in the first sector from Tuticorin to Tiruchendur during December 1986—March 1987. In this study 58 species of marine algae were recorded of which 7 belong to Chlorophyta, 12 to Phaeophyta and 39 to Rhodophyta besides 3 species of seagrasses namely Cymodocea seiriilata, Halophila ovalis and //. ovata within 650 sq. km area surveyed. The total standing crop of the seaweeds was estimated at 9,100 tonnes (wt.). The estimates for the dominant species are Dictyota maxima 530 t, Sargassum tenerrium 640 t, D. bartayresiana 8601, Selieria rebusta 2,0901 and Hypnea valemiae 2,4301. The seaweed potential for commercial exploitation has been briefly discussed

    Distribution of sea weeds off Kattapadu - Tiruchendur coast, Tamil nadu

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    The present paper deals with the distribution of seaweeds and seagrasses during the deep sea survey conducted in the first sector from Kattapadu to Tiruchendur in Tamil Nadu coast between December 1986 and March 1987 covering an area of 650 sq.km. In thiS survey. 58 species of marine algae \\ere recorded. of which 7 belong to Chlorophyta. 12 to Phaeophyta and 39 to Rhodophyta. Three species of seagrasses vi z. Cymodocea serrl/lata. Halophila ovails and H. ovala were also recorded at the depths ranging from 5.5 to 21.5 III Halim eda macroloba, D,ClyOIO barlayresiana, D. Maxima, Gracliaria corl/cala var. corlicala, G. edulis, Sarcodia indica, Sarconema filiform e, Soliena rob"sla, flypnea esperi and H. "alenliae were found to be dominant and widely distributed. Hydrological data were also collected from area surveyed. The atmospheric and bottom water temperature varied from 25.0 to 36.8'C and 26.0 to 31.8'C respectively. The pH ranged from 8.3 to 8.6 and the salinity from 26.39 to 33.430/00 . The dissolved oxygen ranged from 3A2 to 6.47 mill. The phosphate content varied from 0.05 to 0. 15 I'g atm/ l, silicate from 4.00 to 12.00 I'g atmll, nitrate from 0.25 to 1.00 I'g at mil and nitrite from 1.05 to 3.99 I'g atml l
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